The invention relates to a process for preparing 2,3,3,3-tetrafluoropropene. In particular, the invention relates to a process for preparing 2,3,3,3-tetrafluoropropene comprising fluorinating 1,1,1-trifluoro-2,3-dichloropropane and dehydrohalogenating a compound formed from the fluorination to produce 2,3,3,3-tetrafluoropropene.
2,3,3,3-tetrafluoropropene is also known as HFO-1234yf, HFC-1234yf or simply 1234yf. Hereinafter, unless otherwise stated, 2,3,3,3-tetrafluoropropene will be referred to as 1234yf. The known processes for preparing 1234yf typically suffer from disadvantages such as low yields, and/or the handling of toxic and/or expensive reagents, and/or the use of extreme conditions, and/or the production of toxic by-products. Methods for the preparation of 1234yf have been described in, for example, Journal Fluorine Chemistry (82), 1997, 171-174. In this paper, 1234yf is prepared by the reaction of sulphur tetrafluoride with trifluoroacetylacetone. However, this method is only of academic interest because of the hazards involved in handling the reagents and their expense. Another method for the preparation of 1234yf is described in U.S. Pat. No. 2,931,840. In this case, pyrolysis of C1 chlorofluorocarbons with or without tetrafluoroethylene was purported to yield 1234yf. However, the yields described were very low and again it was necessary to handle hazardous chemicals under extreme conditions. It would also be expected that such a process would produce a variety of very toxic by-products. In addition to addressing the disadvantages of the known methods, it would be desirable to provide a new method for the preparation of 1234yf that use only readily available feedstocks.
The listing or discussion of a prior-published document in this specification should not necessarily be taken as an acknowledgement that the document is part of the state of the art or is common general knowledge.